Laser-Driven and Magnetized Ultracold Neutral Plasmas

这个项目将探索等离子体的基本行为，电子和离子的汤，在一个虚拟的“磁瓶”陷阱。 为了了解地球的磁场如何保护生命免受来自太阳的带电粒子流的影响，或者从核聚变中产生清洁能源，人们必须了解等离子体在磁场中的行为。 这是等离子体物理领域的关键问题之一。这个项目将提供一个由磁场捕获的等离子体的行为的详细了解。等离子体将以高度受控的方式产生，从而产生超冷等离子体，其温度比外层空间更低。如此低的温度使得更容易隔离系统中的不同过程进行研究，例如颗粒从陷阱中逃逸的速率。令人惊讶的是，超冷等离子体显示出与热而致密的天体物理等离子体相似的行为，因此这些实验可以回答关于物体性质的基本问题，例如白色矮星，它可以拥有强磁场。该项目还将培训学生广泛的技术技能，使他们能够为STEM劳动力做出贡献。将继续努力进行外联和招募工作，以增加来自不同背景的学生的参与，该项目将把最近开发的用于在超冷中性等离子体（UCNP）中激光冷却离子的工具与磁约束技术结合起来。这为发现等离子体科学提供了令人兴奋的机会，例如表征磁化和库仑相互作用（或“耦合”）强度交叉机制中的平衡和传输现象。结合激光和磁力可以提供一个解决方案，长期存在的挑战，等离子体约束在四极磁场的几何形状，即逃逸的等离子体通过损失间隙沿着场线。强耦合和磁化的结合改变了传输现象和集体模式，并吸引了越来越多的兴趣，从尘埃和高能量密度等离子体社区。这些实验将建立一个新的系统来探测这一物理现象，并将测试最近描述这一领域碰撞过程的理论。具体目标是（1）表征在四极磁场中形成的UCNP的损耗过程和磁约束时间随磁场的缩放，（2）测量磁化离子的自扩散常数并观察强耦合的影响，以及（3）使用激光力来堵塞损耗间隙，该损耗间隙通常允许等离子体在四极磁场中沿着引导中心磁场线逃逸，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project will explore the fundamental behavior of a plasma, a soup of electrons and ions, in a virtual ‘magnetic bottle’ trap. In order to understand how the magnetic field of the Earth protects life from electrically charged particles streaming from the sun, or to generate clean energy from nuclear fusion, one has to understand how a plasma behaves in a magnetic field. This is one of the key problems in the field of plasma physics. This project will provide a detailed understanding of the behavior of plasmas trapped by a magnetic field. The plasma will be created in a highly controlled manner that results in an ultracold plasma, which is colder than outer space. Such low temperatures make it easier to isolate different processes in the system for study, such as the rate at which particles escape from the trap. Surprisingly, an ultracold plasma shows behavior that is similar to hot and dense astrophysical plasmas, so these experiments can answer fundamental questions on the properties of objects such as white dwarf stars, which can possess strong magnetic fields. The project will also train students in a broad set of technical skills so they can contribute to the STEM workforce. Outreach and recruiting efforts will be pursued in order to increase participation by students from diverse backgrounds.This project will combine recently developed tools for laser cooling ions in an ultracold neutral plasma (UCNP) with magnetic-confinement techniques. This offers exciting opportunities for discovery plasma science, such as characterizing equilibration and transport phenomena in crossover regimes of magnetization and Coulomb-interaction (or ‘coupling’) strength. Combining laser and magnetic forces may provide a solution for long-standing challenges to plasma confinement in a quadrupole magnetic-field geometry, namely the escape of plasma through loss gaps along field lines. The combination of strong coupling and magnetization modifies transport phenomena and collective modes, and has attracted increasing interest from the dusty and high-energy-density plasma communities. These experiments will create a new system for probing this physics, and will test recent theories describing collisional processes in this regime. The specific goals are to (1) characterize the loss processes and scaling of magnetic confinement times with magnetic field for UCNPs formed in a quadrupole magnetic field, (2) measure the self-diffusion constant for magnetized ions and observe effects of strong coupling, and (3) use laser forces to plug loss gaps that typically allow plasma to escape along guiding-center magnetic field lines in a quadrupole magnetic field, creating long-term confinement.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.